Impact printers are known in which an impact member strikes a recording medium through a printing ribbon between said impact member and said recording medium. Thus, when the device and its member is in operation, the latter will strike the printing ribbon repeatedly and adherence of a small quantity of ink to the impacting arm cannot be avoided. Even if this quantity of ink is rather small, it will cause problems after a certain time period because ink will successively collect on the arm and pass inwardly along the arm to ultimately reach the part of the arm which coacts with the impact surface upon retraction. Thus, ink on this part of the arm will result in the tendency of the arm to adhere to the impact surface resulting in a reduced printing speed, and additionally possibly make the device inoperative. This occurrence will result in a relatively short servicing interval which, of course, is a disadvantage with regard to both cost and operational safety.
The present invention relates to a device for producing imprints on a recording medium which has a member acting on the medium designed to strike or press against the surface of the medium through a printing ribbon. The member has an elongated arm which is resiliently connected to the frame or other support, and which is securely mounted relative to the operating member so that the arm, under the action of the operating member, is yieldably pivotable between a rear position that is defined by the arm or by a member attached thereto bearing against an impact surface, which is unyielding relative to the support, and a front position which is the printing position.
An object of the present invention is to improve the foregoing imprinting device in such a manner that ink is prevented from moving in between the arm and the impact surface. This object is achieved in accordance with the teachings of the present invention in that the cross-sectional area of the part of the arm which is located between the member acting on the medium and the part of the arm which coacts with the fixed impact surface, is altered by at least one steep step.
A further object of the present invention is to provide a plate in the form of a collar surrounding said arm above said impact surface and functioning as a collecting device for ink dripping down the arm toward the impact surface.
Another object of the present invention is to provide a porous absorbent material mounted in said support for absorbing the ink that is collected in the collar.